Coates has acted in theatre, film, television and radio, with extensive work in Canadian and American television and performing in more than forty stage productions. His work also expands to include writing, producing, teaching and mentoring.

In 2003, he wrote, produced and directed a short film titled Dakota, and for several years, Coates was a drama teacher for Toronto's multi-discipline "SuiteLife Arts for Youth Program."

He has primarily been cast as bit parts, but has carried supporting character roles in several television series, including Kyle XY, The Zack Files, La Femme Nikita, and These Arms of Mine. He played Warden Morgan in several episodes of The Dresden Files, appeared in Percy Jackson & the Olympians: The Lightning Thief as Hephaestus and in Unnatural History as Samuel Tolo, and made a guest appearance in the Fringe episode "What Lies Below" as Vincent Ames. He has also appeared in Supernatural as one of Crowley's demons in the episode "Caged Heat". In 2010 he played Bartik in TRON: Legacy.

Coates currently appears in Saving Hope as Bryan Travers, as well as commercial and film work. He also teaches an acting school under the name "Coates and Company."

Coates was born in London, England. At a young age he moved to Canada, where he was educated. After school, he worked in local and regional theaters and at the Stratford (Shakespeare) Festival. He is married and has at least one daughter whom he delivered himself.